Obstructing giant colonic diverticulum.

We report the second case of an obstructing true colonic diverticulum. Of the 103 cases of giant sigmoid diverticulum found in the literature, 13% have been reported as true giant sigmoid diverticulum, ie, containing all layers of the colonic wall. Our 75-year-old patient had clinical symptoms for only 6 months, and endoscopy revealed an almost totally obstructing mass 20 cm from the anus. Surgical resection of the sigmoid colon with a primary anastomosis resolved all of the patient's obstructive symptoms. A flap-valve mechanism was the cause of this true giant colonic diverticulum. Microscopic examination of the diverticulum wall revealed all normal layers of colon wall.